odd feeding issue with 300 blk AR.

[cartman308]

The rifle is a Daniel Defense M4V7.

Having an issue with a specific factory ammo that I bought a bunch of. The loads in question are Nosler Match Grade with 125 grain Ballistic Tips. Supersonic. I bought 15 boxes buscause the price was right.

Issue is it will not strip second round from the magazine. Seems to be short stroking. if basically turns the gun into a si gle shot.

What makes this odd is PNW Match Hunting ammo (which is loaded with the same projectile) and Remington Priemer OTM (which has a significant longer OAL) cycle perfeclty.

Someone recommended I switch to an H2 Carbine buffer and try again. This seems wrong to me because that buffer is heavier. Granted he knows ARs much better than I, I just want to ask for more opinions before I start throwing money at it.

Gun is clean as a whistle. I wouldnt think it was a gas issue because two other loads function flawless.

I have also tried ten and thirty round pmags. And 300 blackout enhances 30 rounders from Wilson Combat (steel). Same results.

AnY ideas???

Sorry for the typos......... typing on a phone with fat fingers.....

 

[HankC]

Barrel length and gas system make difference, what do you have? New rifle? open up gas port is also an option (what port dia you have?) if you wish to use same lower for your 5.56s.

 

[MistWolf]

From the description given, your rifle is short stroking. Take an empty mag and place one round in it, load it into the rifle, chamber and fire it to see if the bolt locks back. If it doesn't, it's short stroking.

When a rifle is short stroking, going with a heavier buffer usually makes things worse. Occasionally, it will work but I wouldn't bet on it. I'd suggest cleaning & lubing the BCG, trying a lighter buffer and trying a different spring just in case the existing one has gotten worn

 

[cartman308]

Thanks. Thats what I was thinking. The rifle has less than 200 rounds down the tube so I hope the spring isn't shot. Not real sure what buffer Daniel Defense puts in their rifles. Looks like a inquiry to DD is in order.

 

[cartman308]

Its all factory built from Daniel Defense. I will never likely put a 556 upper on it. Usless round for me other than plinking.

 

[jerkface11]

If it has less than 200 rounds thru it there's probably still parkerizing on the rails the bolt carrier rides on. Run a couple hundred more thru it and I bet the problem goes away.

 

[cartman308]

I'll have to pick up some PNW range to burn up and see what happens. I really need this ammo to run. Otherwise I'll be buying a 300 blk bolt gun

 

[rb288]

Yep, buy a few boxes of what you know works and run a few mags.
Then clean and lube real good and try someof the stuff that doesn't work.
My guess is it just needs to be run a bit and wear in some.
Otherwise, your rifle may just not like that stuff, it can happen.
Mine didn't like Remington 120s at first, then started having no ptonlems after a couple hundred rounds.
Good luck, stick with it, it is a good gun.

 

[cartman308]

I love the gun. Many deer have fallen to it. They seem to be allergic. My little girl is laying them down with it to.

The only thing I want to change is the stock. The MOE rattles really bad when I'm waking with it. Carry it to stand with a Magpul MS4 sling. I'm wanting to change to a VLTOR EMOD. Bro in law has one on his mixmaster and I really like it. Would give me a good excuse to play with buffers.

I meant to go to the barn and make sure it was short stroking but havent had time today.

 

[Jackal]

If it only occurs with 1 type of ammo, then likely the ammo is the problem. Sell it and buy what works in your rifle or send your rifle back to DD. A quality AR should never have to "wear in". If its been built to proper specs, it darn well better work right out of the box. Thats like buying a brand new pickup truck that backfires and dies n' saying that it "only needs to wear in" .

 

[jerkface11]

So what's the proper spec for parkerizing on the inside of the upper?

 

[Jackal]

So what's the proper spec for parkerizing on the inside of the upper?

Loose enough for the carrier to slide freely, obviously.

 

[cartman308]

I emailed DD to see what they say. Wont likely send it back unless they highly recommend it. It shoots the PNW very well but I'm not vwry happy with that ammo. The projectiles come loose if they are cycled a few times Manually. we cant transport loaded weapons during hunting season (or anytime for that matter) on an ATV or in a vehicle. and you dont want to fire the chamber every evning after a hunt either.

 

[MistWolf]

If it only occurs with 1 type of ammo, then likely the ammo is the problem. Sell it and buy what works in your rifle or send your rifle back to DD. A quality AR should never have to "wear in". If its been built to proper specs, it darn well better work right out of the box. Thats like buying a brand new pickup truck that backfires and dies n' saying that it "only needs to wear in" .

My personal experience and the experience of others says otherwise.

A rifle that short strokes on a particular lot of ammo is hardly comparable to a new truck that backfires and dies

 

[Tirod]

If it functions with two other loads, but not the one, then it's the gas pressure developed by that lot of ammo. It's not sufficient to drive the BCG back far enough.

The upper isn't "parkerized," it's anodized and shouldn't be that rough. The TM specs most of the lube should go in the upper charging handle slot as that is where the cam pin rides. Lube it heavily as that is spec. Otherwise, the BCG is just laying on the bottom of the upper, one cylinder shape inside another.

Cars and guns do have to break in - we basically operate them enough to have the sliding surfaces wear down the friction points enough to remove the high spots. Rings in pistols must condition the cylinder they ride in, pushrods the ball socket they have contact with, cam lobes the lifter on them. AR's have cam pins in the upper channel, rings in the BCG, lugs rotating against lugs, followers sliding in magazine interiors and rounds stripping out from under feed lips. The list of parts to fluff and buff isn't long, just shooting them does it. Not to mention that triggers have to break in, too - as plenty of shooters have discovered to their delight.

Having it shoot right from day one is nice, but only the military gets that, and the ammo is highly controlled to put out more than sufficient gas pressure. A commercial load made for a non issue commercial caliber means it's subject to that makers whim the day it was loaded. There very much may be a good reason it was cheap - and now you know why.

 

[Blade First]

RE: your noise problem with the MOE...

Are you using a commercial stock on a military tube? Magpul stocks are anything but sloppy.

On the cycling problem, I'd also suggest lube on the buffer spring and buffer. Synthetics like Frog Lube or Lucas Extreme Duty work well for me and will also make it quieter. J&T Distributing sells a product called the 'Twang Buster' which inserts on the rear of the spring and insulates it from the rear of the tube. Makes a large difference, too.

 

[cartman308]

I serioulsy doubt its a commercial tube. I would hope Daniel Defense doesnt even have them in their assembly area.

I've got so many irons in the fire right now I dont know when I will be able to get the rifle going again. Thanks for all the advise so far!